Breath analyzing apparatus having means for evaporating moisture from breath conduit

ABSTRACT

Apparatus for analyzing breath for ethyl alcohol having a breath conduit into which a subject expires in the collection of a sample of breath is provided with means for removing condensed moisture from the conduit. For this purpose, means is provided for supplying air to the conduit following the collection of a sample thereby effecting a flow of drying gas through the passage of the conduit. Advantageously, the air is supplied, after closure of a valve between the conduit and a sample chamber, by an air pump which also serves to expel the sample collected in the chamber to alcohol measuring means.

United States Patent [151 3,647,391

Keyes Mar. 7, 1972 [54] BREATH ANALYZING APPARATUS 3,552,930 l/l97l Borkenstein ..73/42l.5 R

[72] Inventor: Frederick G. Keyes, 15 Berkeley St, Cambridge, Mass. 1

[22] Filed: Jan. 27, 1970 [21] Appl. No.: 6,113

[52] U.S.Cl. ..23/254 R,23/232 R. 73/42l.5 R; 73/422 R [51] Int.Cl ..G01n l/22,G0ln3l/22,G0ln 33/16 [58] Field ofSearch ..23/254,232;73/421.5 R, 422 GC [56] References Cited UNITED STATES PATENTS 3,238,783 3/1966 Wright ..73/42l.5 R

HAVING MEANS FOR EVAPORATING MOISTURE FROM BREATH CONDUIT Primary Examiner-Morris O. Wolk Assistant Examiner-R. M. Reese Attorney-George C. Fuller [57] ABSTRACT Apparatus for analyzing breath for ethyl alcohol having a breath conduit into which a subject expires in the collection of a sample of breath is provided with means for removing condensed moisture from the conduit. For this purpose, means is provided for supplying air to the conduit following the collection of a sample thereby effecting a flow of drying gas through the passage of the conduit. Advantageously, the air is supplied, after closure of a valve between the conduit and a sample chamber, by an air pump which also serves to expel the sample collected in the chamber to alcohol measuring means.

5 Claims, 1 Drawing Figure PATENTEUMAR 7 1972 3,647, 891

[ml/en for Freda/fair Gjf yes By his Attorne y BREATH ANALYZING APPARATUS HAVING MEANS FOR EVAPORATING MOISTURE FROM BREATH CONDUIT BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to improvements in apparatus for analyzing breath for ethyl alcohol.

2. Description of the Prior Art Apparatus for analyzing breath for ethyl alcohol has lately come into extensive use largely as the result of the growing recognition by law enforcement agencies of its utility in distinguishing, among drivers suspected of being under the influence of alcohol, those drivers having an excessive percentage of alcohol in their blood. Many jurisdictions have now enacted laws under which the breath of suspects may be analyzed by such apparatus and have established values for the percentage of blood alcohol which should not be exceeded if a person is not to be regarded as under the influence. Accordingly it is essential that breath analyzing apparatus used for this purpose provide indications which are as accurate as it is possible to make them.

Frequently such apparatus is used to test several subjects in succession. I have discovered that in this situation a source of error may be introduced by the collection of moisture condensed from the breath upon the inside wall of the breath conduit. Such moisture if allowed to remain in the breath'passage will, through interchange in the vapor phase, tend to produce readings which in certain cases are lower than they should be.

SUMMARY OF THE INVENTION It is an object of the present invention to provide improvements in apparatus for analyzing breath, which improvements will overcome the problems caused by the condensation of moisture in a breath input conduit of the apparatus.

Another object of the present invention is to provide means for overcoming the aforesaid problem which will be as economical as possible.

Still another object of the present invention is to provide means for overcoming the aforesaid problem which will not introduce by themselves a possible source of error.

To these ends and in accordance with a feature of the present invention, there is provided, in breath analyzing apparatus having a breath input conduit, means for supplying gas to the breath conduit, whereby after a sample has been collected and the sample chamber closed off from the conduit, a current of gas may be caused to flow through the conduit to remove moisture if present therein.

In accordance with a further feature of the invention, the source of gas conveniently and economically comprises an air pump which also serves the function of expelling the breath sample from the sample chamber to alcohol measuring means.

BRIEF DESCRIPTION OF THE DRAWINGS The FIGURE represents a diagram of apparatus embodying the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the FIGURE, the illustrative apparatus has a container provided with an inlet port 12 and an outlet port 14 between which is formed a sample chamber 15. A breath conduit 16 defining a breath passage, suitably and as shown, a flexible rubber tube, is adapted with a disposable mouthpiece 18 at one end thereof for conducting to the container 10 air expired by a subject into said passage. An inlet valve 20 disposed at the inlet port 12 interconnects the latter with the other end of the conduit 16 and with an air line 22 extending from air pump 24 through a silica gel drier 26. An outlet valve 28 at theport l4 interconnects the latter with a venting whistle and with an outlet duct communicating with means generally referred to by the numeral 33 for sensing and measuring alcohol contained in a sample. The valves 20 and 28 are arranged for solenoid operation between two positions in response to actuation of a pushbutton switch PBl. In the first position with the solenoids energized by closure of the switch PB], the valve 20 provides communication only between the passage of the breath conduit 16 and the container 10 while the valve 28 provides communication only between the container l0 and the whistle 30 so that expired breath may then pass readily from the mouthpiece through the container and out the whistle in the collection of a sample of breath. In the second position of the valves, assumed thereby upon deenergization of the solenoids, communication between the breath passage and the container on the one hand and between the container and the venting whistle on the other is cut off. The valve 20 in its second position provides communication only between the air line 22 and the container 10 while the valve 28 provides communication only between the container and the outlet duct. The air pump is arranged to be driven by a motor M under the control of a timer T initiated by actuating a switch PB2 so that with the valves in their second positions, the vapor contained in the sample chamber 15 will be expelled to the measuring means 33.

The measuring means 33 which may be conventional and which form no part of the present invention suitably may comprise a via] 34 of a solution reactive with any alcohol present in the sample to effect a color change in the solution, and photoelectric means including a lamp 36 and a photocell 38 for sensing the color change in the solution, and indicating means comprising a meter 40.

In collecting a sample of breath in the container 10, the switch P81 is held closed while the subject expires into the mouthpiece 18. When the sound produced by the whistle 30 begins to die down, the switch PB] is released and the valves 20 and 28 assume their second position in which the air line 22 communicates with the container 10 through the port 12 while the container communicates through the port 14 with the duct 32. Then the sample is expelled to the measuring means by closing the switch PB2 which causes the motor to drive the airpump 24 for a predetermined period of an analyzing cycle to bubble the sample through the solution in the vial 34.

Where several persons use the analyzing apparatus in sequence, there is a tendency for moisture to condense in the passage of the breath conduit 16, affecting the accuracy of the reading shown on the meter 40 as explained above. In accordance with a feature of the present invention, means is provided for supplying air to the inner end of the breath conduit 16 during the measuring portion of the analyzing cycle. For

this purpose, a bypass duct 50 is connected at one end to the air line 22 for communication therewith on the pump side of the drier 26. The other end of the duct 50 is connected to the conduit 16 adjacent the valve 20 so that when the pump is driven by the motor M, a current of air is caused to flow along the passage of the breath conduit 16, thereby drying moisture which may be present. The duct 50 is connected to the line 22 on the pump side of the drier to avoid the possibility of entry to the container during the analyzing cycle of any alcohol from breath which may have entered the duct during the collection of a sample and which might otherwise cause the reading to be false.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In apparatus for analyzing breath for ethyl alcohol, said apparatus having means for sensing ethyl alcohol and means comprising a breath conduit defining a breath passage for conducting to said sensing means air expired by a subject into said passage at one end of said conduit, in combination therewith, means connected to said conduit for supplying gas thereto to effect a flow of gas through said conduit for removing moisture from said breath passage.

2. In apparatus for analyzing breath for ethyl alcohol, said apparatus having means for sensing ethyl alcohol and means for collecting samples of breath comprising a container and a breath conduit connected thereto and defining a breath passage for conducting to said container air expired by a subject into said passage at one end of said conduit, in combination therewith means connected to said conduit and comprising a duct communicating with said passage through an opening in the wall of said conduit spaced from said one end and means for supplying the duct with gas for effecting a flow of 5 gas along the breath passage for drying moisture therefrom.

3. ln apparatus for analyzing breath for ethyl alcohol, said apparatus having a container provided with an inlet port and an outlet port, a breath conduit defining a breath passage and having one end adapted to be received in the mouth of a subject and another end connected to said container for conducting thereto through said inlet port air expired by a subject into said passage at said one end of said conduit, an air line having air drying means connected therein, an inlet valve interconnecting said line, said conduit and the inlet port of said container and actuatable between a first position providing communication only between said container and said conduit and a second position providing communication only between said container and said air line, alcohol sensing means and an outlet valve connected to said container for controlling the efflux of gas through said outlet port, said valve being actuatable between a first position in which said outlet port communicates with the atmosphere for venting the container during second position to effect a flow of gas through said conduit for drying moisture from said breath passage.

4. Apparatus as defined in claim 3 in which said duct is connected at its other end to said air line for supply by said air supply means.

5. Apparatus as defined in claim 4 in which said duct is connected to said air line for communication therewith intermediate the drying means and the air supply means, whereby when said inlet valve is in its second position, said duct communicates with said container only through said drying means for the removal of any residual alcohol vapor emanating from said duct. 

2. In apparatus for analyzing breath for ethyl alcohol, said apparatus having means for sensing ethyl alcohol and means for collecting samples of breath comprising a container and a breath conduit connected thereto and defining a breath passage for conducting to said container air expired by a subject into said passage at one end of said conduit, in combination therewith means connected to said conduit and comprising a duct communicating with said passage through an opening in the wall of said conduit spaced from said one end and means for supplying the duct with gas for effecting a flow of gas along the breath passage for drying moisture therefrom.
 3. In apparatus for analyzing breath for ethyl alcohol, said apparatus having a container provided with an inlet port and an outlet port, a breath conduit defining a breath passage and having one end adapted to be received in the mouth of a subject and another end connected to said container for conducting thereto through said inlet port air expired by a subject into said passage at said one end of said conduit, an air line having air drying means connected therein, an inlet valve interconnecting said line, said conduit and the inlet port of said container and actuatable between a first position providing communication only between said container and said conduit and a second position providing communication only between said container and said air line, alcohol sensing means and an outlet valve connected to said container for controlling the efflux of gas through said outlet port, said valve being actuatable between a first position in which said outlet port communicates with the atmosphere for venting the container during the collection of a sample and a second position in which said container communicates with said alcohol sensing means, means for actuating said valves and air supply means connected to said air line and operative while said valves are in their second positions for transferring the contents of the container to said sensing means, in combination therewith, means comprising a duct having one end connected to said conduit adjacent said other end thereof for supplying gas thereto for drying moisture therefrom while said inlet valve is in its second position to effect a flow of gas through said conduit for drying moisture from said breath passage.
 4. Apparatus as defined in claim 3 in which said duct is connected at its other end to said air line for supply by said air supply means.
 5. Apparatus as defined in claim 4 in which said duct is connected to said air line for communication therewith intermediate the drying means and the air supply means, whereby when said inlet valve is in its second position, said duct communicates with said container only through said drying means for the removal of any residual alcohol vapor emanating from said duct. 